diff --git a/CARTRIDGE_PINOUT.md b/CARTRIDGE_PINOUT.md
index 3c2d544..30ef23a 100644
--- a/CARTRIDGE_PINOUT.md
+++ b/CARTRIDGE_PINOUT.md
@@ -25,8 +25,8 @@ A concise 32-pin cartridge interface for expansion modules, storage, I/O, and op
 |   4 | USB_FLAG      | USB-capable flag                        | pull-up            |
 |   5 | USB_DP        | USB D+                                  | pull-down          |
 |   6 | USB_DM        | USB D-                                  | pull-down          |
-|   7 | USB_ID        | USB host/device mode                    | pull-up            |
-|   8 | USB_VBUS      | VBUS sense / optional power             | pull-down          |
+|   7 |               |                                         |                    |
+|   8 |               |                                         |                    |
 |   9 | SD_CMD        | SDMMC command / host->cartridge control | pull-up            |
 |  10 | SD_CLK        | SDMMC clock / host->cartridge           | pull-down          |
 |  11 | SD_D0         | SDMMC data0 (bi-directional)            | pull-up            |
@@ -35,11 +35,11 @@ A concise 32-pin cartridge interface for expansion modules, storage, I/O, and op
 |  14 | SD_D3         | SDMMC data3 (bi-directional)            | pull-up            |
 |  15 | I2C_SCL       | I2C clock                               | pull-up            |
 |  16 | I2C_SDA       | I2C data                                | pull-up            |
-|  17 | I2S_SCLK      | I2S bit clock                           | pull-down          |
-|  18 | I2S_WS        | I2S word select / frame clock           | pull-down          |
-|  19 | I2S_SDOUT     | I2S data out (cartridge->host)          | pull-down          |
-|  20 | I2S_SDIN      | I2S data in (host->cartridge)           | pull-down          |
-|  21 | I2S_MCLK      | I2S master clock                        | pull-down          |
+|  17 |               |                                         |                    |
+|  18 | I2S_WS        | I2S word select                         | pull-down          |
+|  19 | I2S_SD        | I2S data out                            | pull-down          |
+|  20 | I2S_SCK       | I2S clock                               | pull-down          |
+|  21 | I2S_MCLK      | I2S master clock                        |                    |
 |  22 | SPI_MOSI      | SPI MOSI (host->cartridge)              | pull-down          |
 |  23 | SPI_MISO      | SPI MISO (cartridge->host)              | pull-down          |
 |  24 | SPI_SCLK      | SPI clock (host->cartridge)             | pull-down          |
@@ -50,15 +50,15 @@ A concise 32-pin cartridge interface for expansion modules, storage, I/O, and op
 |  29 | UART_TX       | UART TX (cartridge->host)               | pull-up            |
 |  30 | VCC_5V        | supply                                  | N/A                |
 |  31 | GND           | ground                                  | grounded           |
-|  30 | 5V_EXT        | external power supply (optional)        | N/A                |
+|  30 | EXT_5V        | external power supply (optional)        | N/A                |
 
 ## Signal Groups
 
 - Ground: pins 1, 31
 - 3.3V supply: pin 2
 - Cartridge detection: pin 3
-- USB flag: pin 4
-- USB: pins 5-8
+- USB detection: pin 4
+- USB: pins 5-6
 - SDMMC: pins 9-14
 - I2C: pins 15-16
 - I2S audio: pins 17-21